1. Field of Invention
The present invention relates to a multiwavelength barcode reader for reading a barcode, and more particularly to a barcode reader provided with light sources having two or more wavelengths and capable of improving the resolution of a read barcode.
2. Related Art
FIG. 1 is a schematic structural view of a conventional barcode reader. Referring to FIG. 1, a barcode reader 10 (also known as barcode scanner) mainly includes a light source module 101, a driving unit 102, an image capturing module 103, a detection unit 104, a translation module 105, an transmission module 106, and a switch 107. The light source module 101 is formed by a plurality of light emitting diodes (LEDs), and electrically connected to the driving unit 102. The driving unit 102 is electrically connected to the switch 107, and after the switch 107 is turned on, the driving unit 102 is enabled to drive the light source module 101 to generate a light source. The image capturing module 103, that is, a charge coupled device (CCD), is used for capturing an image, and is electrically connected to the detection unit 104 and the driving unit 102. The detection unit 104 is used for detecting whether the image capturing module 103 successfully captures image data about the barcode, and is electrically connected to the driving unit 102. If the image capturing module 103 fails to capture the image data about the barcode, the detection unit 104 enables the driving unit 102 to drive the light source module 101 and the image capturing module 103 again to read the barcode (by means of scanning or image capturing). When the driving unit 102 drives the light source module 101 to operate, the image capturing module 103 is also driven to capture an image of the barcode. The translation module 105 is used for decoding and recognizing the image data about the barcode captured by the image capturing module 103, so as to convert the barcode symbol into information in the form of texts or figures. The transmission module 106 further connects the barcode reader 10 to an information device, such as a computer host, so as to transmit the decoded data to the information device connected thereto. The transmission module 106 has a transmission port as a connection end. The transmission port may be, for example, a USB (universal serial bus) transmission port, a PS/2 (Personal System/2) transmission port, or an RS232 (Electronic Industry Association-Recommended standard-232) transmission port.
FIG. 2 is a flow chart of a process of implementing the conventional barcode reader. Referring to FIGS. 1 and 2, the process includes the following steps.
Step 1, turn on the switch 11: a user presses down the switch 107 to start the barcode reader 10.
Step 2, turn on the light source 12: the driving unit 102 actuates the light source module 101 and the image capturing module 103, and the user aligns light generated by the light source module 101 with the barcode symbol to be captured.
Step 3, capture an image of the barcode 13: the image capturing module 103 captures an image of the barcode.
Step 4, detect 14: the detection unit 104 detects whether the image of the barcode is successfully captured, and if a detection result is “YES”, a translating operation is performed; if a detection result is “NG”, the image capturing module 103 continues to capture the barcode symbol.
Step 5, translate 15: the translation module 105 translates the captured image of the barcode, and converts the barcode symbol into information in the form of texts or figures.
Step 6, transmit 16: the transmission module 106 transmits the converted information to the information device.
In view of the above, in the implementation of the conventional barcode reader 10, when light generated by the light source module 101 is irradiated on a barcode symbol, the image capturing module 103 captures an image of the barcode symbol, and the image of the barcode symbol is translated into data in the form of texts or figures. In practice, most products available at the market have their barcode symbols printed on the external package, and the barcode symbols are generally composed of black bars on a white background. However, to meet the requirement of a nice and consistent package of the products, other colors, for example, red, green, and blue, are used as barcode colors for the barcode symbols when printed on the external package of the products. As the existing barcode reader all provide a single red light source, if the scanned barcode has a background color close to red or has a low color contrast after being irradiated by a red light, the reading of the barcode reader may be affected.